1. Field of the Invention
The present invention relates to a copolymer rubber composition, a rubber foamed product, and an automotive sealant.
2. Related Background Art
For automobiles, sealants sealing between car body opening peripheries, and opening/closing members for openings such as doors and trunk lids are used to prevent rain, wind and sounds from the outside. The sealants commonly include a solid member attached to door frames, trunk lids, car body opening peripheries and the like, and a sponge member to seal gaps between car body opening peripheries, and opening/closing members for openings.
The sponge member is required to be deformable to conform to irregularities and curved shapes of door frames, trunk lids and the like, and to have a hardness which allows close contact with door frames, trunk lids and the like, that is, a reasonable rigidity; and as the sponge member, generally used are rubber foamed products obtained by vulcanizing and foaming an ethylene-α-olefin copolymer rubber.
The sponge member is nowadays required to be reduced in the weight and the costs, and it is being studied that the density of rubber foamed products is lowered (raw materials in rubber foamed products are decreased) by raising the foaming ratio of the rubber foamed products.
For example, Japanese Patent Application Laid-Open No. 2000-344980 and 2002-160327 propose a sponge member composed of a rubber foamed product obtained by vulcanizing and foaming a specified ethylene-propylene-nonconjugated diene copolymer rubber compounded with a crystalline polypropylene resin.